I would stay away from the Samsung 840. Get the 840 Pro or the 830. The regular 840 uses inferior components, which give you less performance and less overall life. Samsung simply cheaped out on that model.

The Agility 4 is a good one, but it's also a budget model which doesn't use the highest quality components. I'd recommend the Vertex 4 since it's faster and you get the 5 year warranty. I've used OCZ drives since the first Vertex, and I've never had a single problem with them. Currently have the 256GB Vertex 4 and it's crazy fast.

I don't have any experience with the Plextor or SanDisk, so I can't say much about either of them.

If you're looking for a budget SSD, go with the Crucial M4. It's cheap, fast, and high quality. I'd say that's definitely your best bet.

afaik there's no physical difference b/w the Vertex and Agility line. Either would be a solid choice.

The Vertex 4 uses a different controller and has much better overall performance. The Agility line is a cut down version of the Vertex 3 line - it performs very similarly in many respects but suffers significantly in others. The Agility isn't a bad choice if you're on a budget—if it's actually cheaper, as it varies—but it's not a true performance drive.

The Vertex 4 uses a different controller and has much better overall performance. The Agility line is a cut down version of the Vertex 3 line - it performs very similarly in many respects but suffers significantly in others. The Agility isn't a bad choice if you're on a budget—if it's actually cheaper, as it varies—but it's not a true performance drive.

Same controller b/w the Vertex 4 and Agility 4. The only difference appears to be synchronous vs asynchronous MLC